Protein staining compositions and methods

Abstract

The present invention provides novel dyes for staining protein, particularly those in elecrophoretic gels. The dyes of the invention are derivatives of Coomassie TM dyes. The invention also provides quantitative and qualitative methods for detecting proteins which comprise staining the proteins with a dye of the invention.

We claim: 
     
       1. A dye of Formula X: ##STR3## or a salt thereof, wherein R 10 , R 20 , and R 30  are independently selected from the group consisting of hydrogen and alkyl of 1-6 carbon atoms; R 40  and R 50  are independently selected from the group consisting of alkyl of 1-6 carbon atoms; R 60  is selected from the group consisting of alkyl of 1-20 carbon atoms, phenyl, alkoxyphenyl, wherein the alkyl group is of 1-10 carbon atoms, and alkylphenyl, wherein the alkyl group is of 1-10 carbon atoms; and R 70  is a group of Formula XI   --(C═O)R.sup.80                                        XI     wherein R 80  is selected from the group consisting of alkyl of 1-20 carbon atoms, phenyl, benzyl, phenyl substituted at any one position with alkyl of 1-10 carbon atoms, chloro, bromo, nitro, or cyano, and benzyl substituted at any one position on the phenyl ring with alkyl of 1-10 carbon atoms, chloro, bromo, nitro or cyano.   
     
     
       2. The dye of claim 1, or a salt thereof, wherein R 10  and R 20  are independently selected from the group consisting of hydrogen and methyl; R 30  is hydrogen; R 40  and R 50  are ethyl; R 60  is selected from the group consisting of ethyl and ethoxyphenyl; and R 80  is selected from the group consisting of alkyl of 1-20 carbon atoms, phenyl and benzyl. 
     
     
       3. The dye of claim 2, or a salt thereof, wherein R 10  and R 20  are both hydrogen or both methyl; R 60  is ethoxyphenyl; and R 80  is selected from the group consisting of n-alkyl of 1-11 carbon atoms and phenyl. 
     
     
       4. The dye of claim 3, or a salt thereof, wherein R 10  and R 20  are both hydrogen and R 80  is n-alkyl of 1-11 carbon atoms. 
     
     
       5. The dye of claim 4, or a salt thereof, wherein R 10  and R 20  are both methyl and R 80  is n-alkyl of 1-11 carbon atoms. 
     
     
       6. The dye of claim 4, or a salt thereof, wherein R 80  is methyl, heptyl, or undecyl. 
     
     
       7. The dye of claim 5, or a salt thereof, wherein R 80  is methyl, heptyl, or undecyl. 
     
     
       8. The sodium salt of the dye of claim 3. 
     
     
       9. The sodium salt of the dye of claim 4. 
     
     
       10. The sodium salt of the dye of claim 5. 
     
     
       11. The sodium salt of the dye of claim 6. 
     
     
       12. The sodium salt of the dye of claim 7.